This is a resubmission of a application developed in response to an RFA concerning studies of the comorbidity of depression with a disruptive behavior disorder (oppositional defiant disorder; ODD) in children and adolescents, a condition that is believed to be particularly resistant to treatment and a precursor to adolescent drug abuse. The first critique of the application led to revisions in data analytic procedures to allow for SEM analysis to examine the overall model more carefully. Incorporating recommendations from reviewers for this resubmission expands the model to incorporate a new variable (attention problems), improves certain measures, incorporates teacher observations, and reintroduces certain elements of the original application to examine subgroups of children with clinically significant levels of ODD and depression. Oppositional defiant disorder (ODD) is the most common psychiatric problem among young children; depression meeting DSM diagnostic criteria is uncommon in preschoolers, but depressive symptoms are not. In studies of depression and ODD among the entire age spectrum of childhood and adolescents, several family, maternal, and child characteristics, along with the mother-child interactional patterns have been identified as risk factors/correlates, with most characteristics seeming to be risk factors for both ODD and depression. While studies of the early origins of ODD exist, relatively few have examined onset of depressive symptoms in young children, and even fewer have examined the development of ODD/depression comorbidity. This proposed study will examine a model included family (conflict, stressors), maternal (depression), child (temperament, school academic competence, social skills problems, attentional problems), and interactional (mother-child interaction, temperament) variables that have received empirical support as precursors to the development of ODD and depression in a large (N=1615) group of children age 4-5 at study onset. Participants will be recruited from public schools and primary care pediatric practices and followed across 3 annual waves of data collection. Primarily using structured equation modeling techniques, overall model fit and the role of specific variables in he development of ODD, depression, and their comorbidity will be examined for both parent and teacher-rated outcomes; additional analyses will examine clinical subgroups.